The document provides detailed notes on cerebral blood circulation, covering the structures involved, their origins, and functions. It highlights objectives for students, such as listing cerebral arteries and understanding arterial and venous vascular disorders. Additionally, it discusses the implications of occlusions and the effects on brain function, along with key anatomical features like the Circle of Willis and vascular supply to the brain's various regions.

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Lecture (16)
▪ Important
▪ Doctors Notes
▪ Notes/Extra explanation
Cerebral Blood
Circulation
‫دفعة‬ ‫عمل‬ ‫عىل‬ ‫ي‬
‫أساس‬ ‫بشكل‬ ‫ي‬
‫مبن‬ ‫العمل‬ ‫هذا‬
436
‫اجعة‬‫ر‬‫الم‬ ‫مع‬
‫للمذاكرة‬ ‫ي‬
‫األساس‬‫المصدر‬ ‫عن‬ ‫ي‬
‫يغن‬ ‫وال‬ ‫المالحظات‬ ‫وإضافة‬ ‫والتدقيق‬

2. ▪ Objectives
At the end of the lecture, students should be able to:
✓ List the cerebral arteries.
✓ Describe the cerebral arterial supply regarding the origin,
distribution and branches.
✓ Describe the arterial Circle of Willis .
✓ Describe the cerebral venous drainage and its termination.
✓ Describe arterial & venous vascular disorders and their clinical
manifestations.

3. Cerebral Circulation
o It is the movement of blood through the network of blood vessels to
supply the brain.
o The movement of blood in the cerebral circulation is called cerebral
blood flow.
o The arteries carry oxygenated blood and other nutrients to the brain.
o The veins carry deoxygenated blood back to the heart removing carbon
dioxide and other metabolic products.
o The two anterior cerebral circulations (left and right) are connected to
each other by ONE anterior communicating artery.
o The anterior circulation (carotid) is interconnected to the posterior
circulation (basilar) via bilateral TWO posterior communicating arteries.
o Posterior communicating arteries are part of Circle of Willis.
Only on the boy’s slides
Extra

4. The arterial supply of the cerebrum is
composed of/provided by 2 arterial systems:
1) Carotid System (Posterior cerebral circulation)
Composed of:
• Internal carotid artery and its branches:
• Anterior cerebral artery* (smaller)
• Middle cerebral artery* (bigger)
Supply anterior portion of brain
The two vertebral arteries (from the subclavian
artery) unite to form basilar artery*.
It divides at the upper border of pons into two
posterior cerebral arteries*
Supply posterior portion of brain
Extra
*We will talk about these in more detail later.
Cerebral Arterial supply
Extra
2) Vertebro-Basilar System (Posterior cerebral circulation)

5. Origin Internal carotid artery Basilar artery
Branch
Anterior Cerebral Artery
(ACA)
Middle Cerebral Artery
(MCA)
Posterior Cerebral Artery
(PCA)
Supplies
1. Orbital and medial
surfaces of frontal and
parietal lobes.
2. A narrow part on the
superolateral surface.
Entire Superolateral surface*:
1. Somatosensory Cortex
2. Motor Cortex
3. Language areas:
• Broca's Area: linked to speech
production.
• Wernicke’s Area: It is involved in
the understanding of written and
spoken language
4. Auditory areas:
• Primary auditory area
• Heschl’s Gyrus: to process
incoming auditory information
1. Anterior and inferior temporal
lobes
2. Uncus:
• Located on the tip end of the
medial surface of the
parahippocampal gyrus.
• Part of the olfactory cortex
that processes information
from the sense of smell.
3. Inferior temporal gyri
4. Inferior and Medial Occipital
lobe (visual area)
*Except for a narrow part by the ACA, MCA supplies all the motor area except the leg area. (Snell) except foot and genitals
Cerebral Arterial supply

6. Medial Surface of
Cerebral Hemisphere
Superolateral
Surface of Cerebral
Hemisphere

7. Basilar artery
o The vertebral arteries unite at the lower border of the pons to form the basilar artery.
o Pontine: related to the pons.
o Its formed by 2 vertebral artery
Only on the boy’s slides
Supplies: Mid brain and cerebellum
Branches: • Anterior inferior cerebellar artery.
• Pontine branches.
• Superior cerebellar artery.
Extra

8. o It joins the carotid and vertebrobasilar systems**.
o It is located on the base of the brain to supply deep structures
o It encircles (surrounds):
1. Optic chiasma.
2. Hypothalamus.
3. Midbrain.
4. Pituitary gland
*Named after Thomas Willis (1621–1675), an English physician.
** the circle of Willis is Formed by the anastomosis between the two internal carotid arteries and the two
vertebral arteries. (Snell)
Playlist
Extra
It is formed by:
Two internal carotid arteries
Two anterior cerebral arteries
Two posterior cerebral arteries
Two posterior communicating arteries
One anterior communicating artery
Circulus Arteriosus (Circle of wills*)
IMPORTANT

9. o Branches: Perforating arteries
numerous small vessels that penetrate the surface of the brain
through the anterior and posterior perforating substances.
o They are divided into:
Anterior Perforating Arteries Posterior Perforating Arteries
Arise from:
• Anterior cerebral artery.
• Anterior communicating artery.
• Middle cerebral artery.
• Posterior cerebral artery .
• Posterior communicating artery.
Enter brain
through:
• Anterior perforated substance
(an irregularly quadrilateral (having 4 sides)
area in front of the optic tract and behind
the olfactory trigone).
• Posterior Perforated substance.
(perforated substance: a layer of grey
matter, that is pierced to allow blood
vessels to pass)
Supplies
1. Large part of basal ganglia.
2. Optic chiasma.
3. Internal capsule ( a white matter
structure).
4. Hypothalamus .
1. Ventral portion of Midbrain.
2. Parts of Subthalamus and
Hypothalamus.
Circulus Arteriosus (Circle of wills)

10. Angioma
Aneurysm
Stroke
Arterial Disorders
• It happens when blood supply
to the brain is interrupted or
reduced.
• Sudden occlusion
• It can be: Ischemic or
hemorrhagic.
• localized, blood-filled balloon-
like bulge in the wall of
a blood vessel.
• Dilation of the wall (may take
years)
• benign tumors derived from
cells of the vascular or
lymphatic vessel walls
(epithelium) or derived from
cells of the tissues surrounding
these vessels.

11. Effects of Occlusion of Cerebral Arteries

12. Effects of Occlusion of Cerebral Arteries (Manifestations)
(Important may come as scenario)
Optic radiation: axons from the neurons in the lateral geniculate nucleus to the primary visual cortex.
Hemianopsia: decreased vision or blindness in half the visual field.
Homonymous hemianopsia: the loss of half of the visual field on the same side in both eyes (see picture on right).
Cortical blindness: total or partial vision loss because of damage to the occipital cortex.
Anterior
cerebral artery
Extra
Artery
Anterior Cerebral
Artery (ACA)
Middle Cerebral Artery
(MCA)
Posterior Cerebral
Artery
(PCA)
Effect
1- Motor disturbance in
contralateral distal leg
2- Difficulty in
prefrontal lobe
functions:
• Cognitive thinking
• Judgement
• Motor initiation
• Self monitoring
1- Contralateral weakness of:
face, arm & hands “more than legs”
• 2- Contralateral sensory loss of:
face, arm, and hands more than
legs
• Visual field cut (damage to optic
radiation)
4- Aphasia (language disturbance):
• In Broca’s area: production
• In Wernicke’s area: comprehension
1- Visual disturbances:
• Unilateral lesion:
contralateral
homonymous
hemianopsia
• Bilateral lesions: cortical
blindness, patients
unaware they cannot
see (Anton’s Syndrome)
2- Memory impairment: if
temporal lobe is affected
IMPORTANT

13. o The veins are thin walled and are devoid of (don’t have) valves.
o The cerebral veins are:
• Found in the subarachnoid space
• Drain the cortical surface
I. Superficial cortical veins II. Deep veins
• Drain the deep structures
These veins
ultimately drain
into:
Dural
venous
sinuses
Cerebral Venous Drainage

14. Extra
They lie on the brain surface, in the subarachnoid
space. They are divided into:
Superior
anastomotic vein
Transverse sinus
Course Termination Notes
Superior
cerebral
veins
• Drain lateral
surface of brain
above the
lateral sulcus
• Terminate mainly into
the Superior Sagittal
sinus, and partly into
superficial middle
cerebral vein
• 6 to 12 veins
Inferior
cerebral
veins
• Run below the
lateral sulcus
• Terminate partly into
superficial middle
cerebral vein & partly
into Transverse sinus.
• Drain the lateral surface of
the temporal lobe
Superficial
middle
cerebral
veins
• Runs along the
lateral sulcus
• Terminates into the
Cavernous sinus
• Connected posteriorly by
Superior & Inferior
anastomotic veins to
Superior Sagittal &
Transverse sinuses
respectively
Cerebral Venous Drainage
I. Superficial Cortical Veins

15. Deep cerebral
veins
2 Internal
cerebral veins
Great cerebral
vein
Straight sinus
They merge to
form:
The two veins unit in
the midline to form:
This short vessel joins the
Inferior Sagittal sinus to form:
They drain the internal structures:
• Basal ganglia
• Internal capsule
• Thalamus
Cerebral Venous Drainage
II. Deep Veins

16. o The Superior Sagittal Sinus
• Lies along the superior border of the falx cerebri and empties into the confluence of sinuses.
o The Inferior Sagittal Sinus
• Lies in the inferior border of the falx cerebri.
• The great cerebral vein of Galen joins the inferior sagittal sinus to form the straight sinus.
o The Transverse Sinuses
• Originate on each side of the confluence of sinuses.
• Each transverse sinus travels laterally, and curves downward to form the sigmoid sinus that
empties into the internal jugular vein on the same side.
o The Confluence of Sinuses
• At the confluence of sinuses, the superior sagittal, straight, transverse, and occipital .
sinuses join.
o The Cavernous Sinuses
• Located on each side of the sphenoid bone.
• Ophthalmic and superficial middle cerebral veins drain into these sinuses.
o The Sphenoparietal Sinuses
• Located below the sphenoid bone and drain into the cavernous sinus.
o The Sigmoid Sinuses
• Receive blood from posterior dural venous sinus veins.
Only on the boy’s slides
Cerebral sinuses

17. o Formed by the union of the right and left brachiocephalic veins.
o Brachiocephalic veins are formed by the union
o Of internal jugular and subclavian veins.
o Drains venous blood Superior vena cava
o from:
o Head, neck, thoracic wall & upper limbs
o It passes downward and enter the right atrium.
Only on the boy’s slides
Superior vena cava

18. o The dural venous sinuses are grouped into:
o Blood flows from transverse & sigmoid
sinuses into IJV Internal Jugular Vein.
Single:
Superior sagittal
Inferior sagittal
Straight
Occipital
Paired: (right & left)
Transverse
Sigmoid
Cavernous
Petrosal (superior &
inferior)
Dural venous sinuses

19. o Obstruction of venous drainage of the brain leads to
Cerebral swelling (edema) and raised Intracranial
Pressure.
• refers to tissue death (necrosis) that is
caused by a local lack of oxygen due to
obstruction of the tissue's blood supply
Infarction
• SSS (superior sagittal sinus) thrombosis*:
can complicate ear infection
• Cavernous sinus thrombosis: As a
complication of infection in the dangerous
area of the face**
Sinus
thrombosis
*Superior sagittal sinus thrombosis (SSST) is the most common type
of dural venous sinus thrombosis and is potentially devastating
**
Extra
Venous Disorders

20. These 2 videos summarize the lecture:
(to view them download the ppt version)
Duration: 01:42 Duration: 01:18
Only on the boy’s slides

21. Cerebral arterial supply
Carotid system
Vertebro basilar system Circulus arteriosus (of willis)
Divides into two posterior
cerebral A
Middle cerebral A
Anterior cerebral A
Supplies : 1.orbital
& medial surfaces of
frontal and parietal
lobes
3.Narrow part on
the superolateral
surface
Supplies entire
superolatral surface:
1.Motor cortex
2.somatosensory cortex
3.Language areas (Broca
& Wernicke)
4.primary auditory area +
association (heschl)
Supplies:
1.Anterior and
inferior parts of
temporal lobe
2.Inferior temporal
gyrus
3.uncus
4.Inferior and
medial parts of
occipital lobe
Internal carotid artery
Joins carotid and vertebrobasilar
systems
Composed of :
• 2 anterior cerebral
A
• 2 internal carotid A
• 2 posterior cerebral
A
• 2 posterior
communicating A
• 1 anterior
communicating A
Branches :
APA
Supply :
1. Large part of
basal ganglia
2. Optic chiasma
3. Internal
capsule
4. hypothalamus
PPA
Supply :
1. Ventral portion
of midbrain
2. Parts of
subthalamus and
hypothalamus
Summary

22. Cerebral venous drainage
Superficial cortical veins Deep cortical veins
Superior cerebral veins
(6-12)
• Drain lateral
surface of brain
above the lateral
sulcus
• Terminate mainly
into superior
sagittal sinus and
partly into
superficial middle
cerebral vein
Inferior
cerebral V
• Drain the lateral
surface of the
temporal lobe
• Terminate partly
into superficial
middle cerebral
vein& partly into
transverse sinus
Superficial middle
cerebral V
• Terminates into
cavernous sinus
• Connected
posteriorly by
superior & inferior
anastomotic vein
to superior sagittal
& transverse
sinuses
respectively
Drain the internal
structures (basal
ganglia , internal
capsule , thalamus)
Internal cerebral veins
Great cerebral vein
Straight sinus
Summary

23. MCQs
(1) What does the basilar artery supply?
A) Mid brain B) Cerebellum
C) A&B D) Motor cortex
(2) Which of the following are paired Dural sinuses?
A) Inferior sagittal B) Straight
C) Cavernous D) Occipital
(3) Which of the following is the one of the effects that occur
when the posterior cerebral artery is occluded?
A) Visual disturbances
B) Language disturbances
C) Motor disturbance in the contralateral distal leg
D) Contralateral sensory loss of face
(4) Which of the following supplies the optic chiasma?
A) Anterior perforating arteries
B) Posterior perforating arteries
C) Middle perforating arteries
D) Anterior cerebral artery
(5) What does the the circle of willis not encircle?
A) Optic chiasma B) Hypothalamus
C) Midbrain D) Cerebellum
(6) Which of the following is not a branch of the basilar artery
A) Anterior inferior cerebellar artery.
B) Pontine branches
C) Superior cerebellar artery
D) Middle cerebral artery
(7) What do the cerebral veins NOT drain?
A) Basal ganglia B) Internal capsule
C) Thalamus D) Hypothalamus
(8) Which of the following runs below the lateral sulcus:
A) Superficial cerebral veins B) Inferior cerebral veins
C) Superficial cerebral artery D) Inferior cerebral artery
(9) A patient Came to the hospital and his family noticed
difference in his personality and he cant make decisions,
what is the most likely diagnosis?
A) Middle cerebral artery occlusion B) Superior sagittal sinus
C) Thrombosis anterior cerebral artery
D) Right temporal and right nasal Fibers
(10) Blood filled bulge in the wall of a blood vessel?
A) Stroke B) Aneurysm
C) Angioma D) Sinus thrombosis

24. Answers
(1) C (6) D
(2) C (7) D
(3) A (8) B
(4) A (9) C
(5) D (10) B

25. SAQ
(1) From which arteries do the anterior perforating arteries arise fro,
• Anterior cerebral artery
• Anterior communicating artery
• Middle cerebral artery
(2) Which parts do the posterior perforating arteries supply?
• Ventral portion of Midbrain
• Parts of Subthalamus and Hypothalamus
(3) A 35 year old man came to the hospital complaining of impaired
memory and cortical blindness.
(A) Which cerebral artery is affected?
Posterior cerebral artery
(B) Which side is most likely affected?
Bilateral lesion (affecting both sides) which will lead to Anton’s syndrome

26. Team Leaders:
Faisal Fahad Alsaif
Rawan Mohammad Alharbi
Team Members:
Abdulaziz Aldukhayel
Abdulrahman Alduhayyim
Rinad Alghoraiby
Rawan Mishal
Good luck
Special thank for team436
▪ References:
1.Girls’ & Boys’ Slides
2.Greys Anatomy for Students
3.TeachMeAnatomy.com
Twitter.com/Anatomy437
Anatomyteam.437@gmail.com